Dropbox Paper - A collaborative document-editing service

Google Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.

Evernote - Bring your life's work together in one digital workspace. Evernote is the place to collect inspirational ideas, write meaningful words, and move your important projects forward.

Bit.ai - Bit is a smart real-time document collaboration platform for teams to create interactive documents, manage digital content and track document insights.

Ghostnote - Add notes to anything.

Apple iWork - iWork is an office suite by Apple.